Updated page Anthropogeny.net now moved to BiokoApes.com
The earliest human DNA ('Y-DNA Adam') and language (Khoi-San with 'clicks') are in western Africa, from about 200,000 years ago. But how could domesticated and anatomically modern humans (people, not apes) have evolved in Africa, without leaving an older fossil record of their history? Where was the large early population with 'ghost DNA' actually living?
I think humans evolved on Bioko Island in a Galapagos-like scenario:
Chimpanzees live in western Africa where there are no fossils of any mammal, because the bones decay too fast. About 6 million years ago, a few chimps may have rafted to the new volcanic islands of Proto-Bioko. There were no trees and no large predators. The only food was marine: seaweeds, shellfish, crabs, sea-turtle eggs and sea-turtle meat. Hundreds of huge turtles visit the beaches each night to lay eggs. The apes had marine food all year, and rain nearly every day.
Those marine apes became human, probably within the first million years: they evolved a bald body, blubber, large brain from a marine diet, a human nose, descended larynx for diving (and speech), multipyramidal kidneys for excess salt, hidden estrus, and other uniquely human traits. The marine selection pressures can explain all the differences between humans and chimpanzees.
For the next 5 million years, I envision a population of 1000 to 10,000 naked marine humans living on Bioko, mostly in the saltwater. They developed advanced language, sang about turtles, shared food. Bioko is warm and cloudy. They had no need to invent fire, or clothes, shoes, tools, or weapons. About 20 to 200 people died each year and their bodies were respectfully buried at sea.
Some of the humans (Homo erectus, Neanderthals, etc.) got over to the mainland and left fossils. Most stayed on Bioko until 200,000 to 50,000 years ago, then walked over on the Pleistocene land bridge. They invented clothing, weapons, and fire — needed to survive in Africa and Eurasia.
This paradigm of an isolated marine habitat can cut the 'Gordian knot' of human evolution. But thousands of scientific careers are dedicated to 'untying' that knot, so no one wants it to be 'cut'.